Sensors have been used in prior art laser processing machines to continuously follow the welding seam during laser welding. The sensor can monitor the exact position of the joint, and, in conjunction with a regulation and control unit, maintain tolerances during the welding process. It is thereby ensured that the laser welding head is always located directly above the joint. Welding seam tracing sensors and/or process control sensors are important mainly when used in connection with industrial robots, for example, for controlling the seam geometry of the weld. Process control is also important in addition to welding seam tracing. Thus, during laser processing, the degree of coupling of the laser beam, the production of splashes, and the welding depth can be monitored.
An additional way to supplement a laser welding process is by supplying a solid or gaseous additional material, for example, a process gas or a wire, during the welding.
The sensor and/or the means for supplying the additional material are generally disposed at a corresponding separation distance from the laser welding beam. The sensor is directed either at an angle toward the processing point (i.e., the sensor “faces” the processing location at an angle) or is located in a perpendicular orientation to a location in front of or behind the processing location (i.e., the sensor does not “face” processing itself, but a location that is leading or trailing relative to the processing location). However, because the laser beam typically is directed toward the workpiece from directly above the workpiece, the sensor or other supplementary laser processing element cannot also be located directly above the workpiece, because it would interfere with the laser beam or the laser beam optics. Thus, because of the orientation of the sensor (or other supplemental elements) with respect to the laser beam, in conventional arrangements, an exact rapid response by the sensor or by the additional material in three-dimensional laser processing is difficult or requires demanding technical solutions. For example, additional axes to move the sensor or the additional material can be required. The supplied data is either distorted or is not derived from the process itself. A further disadvantage is the increased size of the head, and the so-called interference contour.